The EX factor! One Direction's Harry Styles celebrates his 19th birthday on a night out with former flame Caroline Flack

They caused controversy with their 15-year age gap when they enjoyed a brief romance in late 2011.

But it would seem Harry Styles and Caroline Flack are still very much the best of friends after they enjoyed a night out celebrating the One Direction singer's 19th birthday on Thursday evening.

The 33-year-old TV presenter was spotted leaving London's exclusive Groucho Club after a night of celebrations with her former toyboy and a group of showbiz pals.

The ex factor! Caroline Flack helped former flame Harry Styles celebrate his 19th birthday at the Groucho Club on Thursday night

Looking a little bleary-eyed as she emerged from the nightspot, the Xtra Factor host wrapped up in a cosy chocolate brown faux fur coat while making sure to parade her prized pins in a black lace trim minidress and monochrome block heels.

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And in spite of parting ways from her teenage lover over a year ago, it would appear the brunette star was still concerned with looking her very best for her evening out.

Writing on her Twitter page, Caroline said: 'Just had a massive argument with my fringe.'

Here come the boys! Harry was joined by best pals Nick Grimshaw and James Corden for a bite to eat at La Bodega Negra before heading to the Groucho Club

Someone had a good night: Caroline looked a tad bleary-eyed as she left the exclusive nightspot

A friend in need: Caroline's pal wrapped her arm around her neck protectively as they made their way home from the bash

Birthday boy Harry looked his typically dapper self as he left the central London venue, showing off a hint of his chest tattoo in a low cut white T-shirt, which he teamed with a navy blazer and black skinny jeans.

Grinning from ear-to-ear, the teenage heartthrob seemed pleased as punch with the turnout for his night of celebrations.

Prior to heading to the Groucho Club, Harry enjoyed a meal at La Bodega Negra with best pals DJ Nick Grimshaw, 28, and actor James Corden, 34.

Boys' night out: James, Harry and Nick seemed to be in great spirits as they prepared for their big evening out

Birthday boy: Harry was celebrating turning 19 on Friday with a big night out alongside a plethora of his showbiz pals

Chatting away and sharing a joke as they made their way down the street, the trio of showbiz chums appeared to be in great spirits as they toasted the star's last birthday as a teenager.

Although he was certainly in a sprightly mood as he arrived at the Groucho Club, Harry kept his head down as he left, suggesting he may have enjoyed one or two birthday beverages with his friends, before continuing the celebrations at Base nightclub until 3.20am.

Also spotting leaving the exclusive nightspot after Harry's party were presenter Zara Martin and Hollywood actor Jason Statham, who didn't seem to be in a great mood as he departed the club.

Comedic value: Comedian James and DJ Nick seemed to be providing the humour for the evening, and seemed to be sharing a joke as they entered the club

Someone stayed off the booze: While Corden looked a little worse for wear as he emerged from the club, Grimshaw looked bright-eyed ahead of his early rise to present the Radio 1 Breakfast Show on Friday morning

But apparently absent from the celebrations were the singer's One Direction bandmates, Louis Tomlinson, Zayn Malik, Liam Payne and Niall Horan.

It would seem Harry was feeling a little sorry for himself as he awoke on Friday morning, bemoaning the fact that it was his last birthday as a teenager.

He tweeted: 'I feel olllllllllllldddddddddddd.'

Concentrating on the pavement? Harry kept his head down as he left the Groucho Club before heading to Base nightclub until 3.20am

Caroline and Harry enjoyed a three-month romance in late 2011, when she was 32 and he was just 17.

And although the relationship attracted widespread criticism, the TV presenter - who was formerly linked to Prince Harry - publicly defended the pairing.

In an interview with Now magazine at the time, she said: 'I keep thinking, "What have I done wrong?" But I haven’t done anything wrong. What’s hard for me to get my head around is people saying it’s disgusting. I don’t think it is.

Star-studded: Zara Martin and Jason Statham were also among the guests in attendance at Harry's bash

Grouchy at Groucho? Jason Statham seemed somewhat annoyed as he left the club, pushing a fellow reveller out of the way as he attempted to make his way to a taxi

'I feel like I shouldn’t have to worry about what I do. But it’s a social thing that people aren’t accepting of big age gaps.

'Some people tend to see the negative immediately and that's what I find really strange.

'If two people like each other and get on, why does anyone else find a negative in it? I know it's human nature for everyone to gossip. But why say it's bad? No one's being hurt at all in any way. '

Preparing for the night out: Before heading out, Harry enjoyed a game of football with bandmate Louis Tomlinson and Australian boyband 5 Seconds of Summer

New pals: Harry tweeted a snap of him and Louis with their sporty buddies

Motor fanatic Harry appeared to have celebrated his 19th year by adding yet another car to his already extensive collection, this time a classic white 1970s Ford Capri.

Prior to his birthday night out, the singer let off some steam by enjoying a game of football with bandmate Louis Tomlinson and Australian band, 5 Seconds of Summer.

Posting a snap of the group on his Twitter page, he wrote: 'Louis and I just gave the @5secsofsummer boys a footballing lesson!!!'

Keeping fit: Louis and Harry seemed to be sharing a joke as they stopped for a spot of refreshment

Kick-around: Harry and his new pals spent the evening at Linford Christie Sports Centre in West London before the star headed out on the town